refactor: change provide(...) for {provide: ...}

- provide() is deprecated,
- {} syntax is required by the offline compiler

modules/playground/src/order_management/index.ts

@@ -1,10 +1,6 @@
 import {bootstrap} from '@angular/platform-browser';
 import {
   Component,
-  Directive,
-  Host,
-  forwardRef,
-  Provider,
   EventEmitter,
   Injectable,
   Input,